Consumers Find Investors Eager to Make 'Peer-to-Peer' Loans

SAN FRANCISCO—At the new headquarters of Prosper Loans Marketplace Inc., the mission was spelled out on a whiteboard: "NEED $28,676,530.13."

That is how much more Prosper wanted to lend to consumers by the end of June to hit a $30 million target. The twist: The money would come mainly from individual investors who trawl the company's website looking for borrowers willing to pay them attractive returns.